The objectives of this investigator are to investigate the mechanism of action and biological significance of cell-cell adhesion molecules (CAMs) during development of the vertebrate embryo. The major focus of this work is the neural cell adhesion molecule (NCAM), which is a broadly distributed cell surface protein whose binding functions and unusual polysialic acid (PSA) moiety influence a wide variety of cell interactions. A multidisciplinary approach is proposed that includes analyses of the purified glycoprotein, membrane vesicles, cDNA transfected cells, and intact tissues from enzymatically or genetically altered embryos. Individual experiments focus on characterization of the functional domains of NCAM, on the regulated biosynthesis of PSA, as well as an analysis of the role of the NCAM polypeptide and PSA isoforms in a variety of well established developmental systems.